Piston for internal-combustion engines



April 2, 1929. K. HIMMELSBACH PISTON FOR INTERNAL COMBUSTION ENGINES Filed Aug. '7, 1925 Patented Apr. i 2, 19 29."

unrrso STATES PATENT OFFICE.

KARL HIMMELSBACH, 0F ESSEN, GERMANY, ASSIGLIOR' TO FRIED. KRUPP AKTIEN- GESELLSCHAFT, 0F ESSEN-ON-THE-RUHR, GERMANY.

PISTON FOB INTERNAL-COMBUSTION ENGINES.

Application filed August 7, 1925, Serial No. 48,849, and in Germany September 1, 1924.

lhe height of the temperature of the surface of the piston head or of'such inserted body member is limited by theresistibihty of the material used against heat, by regards to the security of working and by the highest pressure of combustion; on the other hand, this temperature should not fall below a certain minimum amount in order that the necessary quantity of heat may be communicated to all fuel drops within the short space of time at disposal. Now, in order not to i pass below a temperature of the piston head recognized as being still effective and to exceed this temperature as little as possible be cause of the afore-said circumstances to be taken into consideration, the invention has for its object to govern the heating of the fueldrops systematically by a peculiar formation of the active surface of the piston head or inserted body member in such a manner as to cause all fuel particles to absorb heat as uniformly as possible when they strike on the piston head or'lnserted body member.

, According to the invention, this object is v essentially attained by making the piston head or inserted body member of such a shape that it presents to the fuel rays striking against it a surface which is as large as possible, and that each fuel drop strikes on a portion of .the surface which is as little as possible cooled by preceding fuel drops of the same injection.

An embodiment of the subject-matter of the invention as applied to a piston provided with an inserted body member is illustrated in the" accompanying drawing in which I V Fig. 1 is a longitudinal section through the piston in a cylinder indicated diagrammatically, and

' ,Figs. 2 and 3 show diagrammatically two other positions of the piston 1n the cylmder.

The piston body A which is provided in the usual way with piston rings a, carries in a recess of the piston head an inserted body member B, the same being inserted with lateral play so that it may freely expand. The insertedbody member 13 is connected with the piston A by means of a stud-bolt C screwed into the inserted body member 1i and a nut 0 According to the invention, the surface of the inserted body member I) lying towards the combustion room is formed in the longitudinal section along a wave-line heaving a crest of the wave situated on the axis of the piston and between the points at which the fuel strikes the piston. The ins erted body member thus shows a central projection b which subsides towards the margin into a trough-like annular depression 6 By shaping the inserted body member as described it is attained that the angle which the fuel rays leaving the nozzle at I) under a constant angle 3 form with the tangent to the wave-line at the point of impact, graduaally increases during the process of injection and that a surface as large as possible is presented to the fuel rays and that each fuel drop strikes on a point ofthe surface little cooled by the preceding fuel drops of the same injection, whereby all fuel particles are caused to absorb the heat uniformly and consequently a good combustion is attained.

In the position of the piston shown in Fig. 1, which corresponds to the beginning of the process of injection, a fuel ray strikes on the inserted body member at the point 1, in the intermediateposition according to Fig. 2 it strikes on the member at the point 2 and at the end of the injection when the piston takes the position according to Fig. 3, the fuel ray strikes on the member at the point 3. The point of impact of the fuel ray moves therefore on the distance 1 to 3. This distance is essentially larger than the corresponding distance of the inserted body members of the pistons now in use which "have either a flat smooth surface or a shallow depression as indicated in dot-and-dash lines in the drawing. In this last-mentioned form which is still a little more favorable than the inserted body members with a flat surface, the points of impact of the same fuel ray would lie at 1*, 2 and 3*; a comparison of the distances 1 to 3 and 1" to 3* shows that the former dis- I tance is about double as large as :the latter. Claim:

This means that the surface available for In an internal combustion engine, a cylinthe heating of all fuel particles is consider-' der, a piston in said cylinder, and means for ably larger with an inserted body member injecting non-vaporized fuel into said cylin- 20 5 according to the invention than with the der toward said piston in obliquely directed known plstons, and therefore a better efi'ect streams, the surface of the piston toward the is obtained. fuel injector being of such shape that in any The invention is more particularly adapted diamet-rical longitudinal section of the piston or use in internal combustion engines in it appears asawave line curving downwardly 25 10 which the fuel is injected without the aid and outwardly from the points at which the of compressed air because, in this case, the fuel strikes the piston in its upper dead center fuel rays mostlyare more coherent and thereposition and then curving upwardly. fore the local cooling of the inserted body The foregoing specification signed at C0- member is greater, but it offers also advanlogne, Germany, this 15th day of July, 1925. 15 tages in engines where the injection is efiected by means of compressed air. KARL HIMMELSBACH. 

